@article{Dang:2004:PPT:985565.985571,
    Address = {Essex, UK},
    Author = {Dang, Zhe and Bultan, Tevfik and Ibarra, Oscar H. and Kemmerer, Richard A.},
    File = {Past Pushdown Timed Automata and Safety Verification - Dang, Bultan, Ibarra, Kemmerer (0) (0) - a - a - q.pdf},
    ISSN = {0304-3975},
    Journal = {Theor. Comput. Sci.},
    Keywords = {Presburger arithmetic, automated verification, past formulas, temporal logic, timed automata},
    Month = {February},
    Number = {1},
    Pages = {57--71},
    Publisher = {Elsevier Science Publishers Ltd.},
    Title = {Past Pushdown Timed Automata and Safety Verification},
    URL = {http://dx.doi.org/10.1016/j.tcs.2003.10.004},
    Volume = {313},
    Year = {2004},
    acmid = {985571},
    bdsk-url-1 = {http://dx.doi.org/10.1016/j.tcs.2003.10.004},
    date-added = {2014-10-29 12:51:43 +0000},
    date-modified = {2014-10-29 12:51:43 +0000},
    issue_date = {16 February 2004},
    numpages = {15},
    doi = {10.1016/j.tcs.2003.10.004}
}

@article{Dang:2004:PPT:985565.985571, Address = {Essex, UK}, Author = {Dang, Zhe and Bultan, Tevfik and Ibarra, Oscar H. and Kemmerer, Richard A.}, File = {Past Pushdown Timed Automata and Safety Verification - Dang, Bultan, Ibarra, Kemmerer (0) (0) - a - a - q.pdf}, ISSN = {0304-3975}, Journal = {Theor. Comput. Sci.}, Keywords = {Presburger arithmetic, automated verification, past formulas, temporal logic, timed automata}, Month = {February}, Number = {1}, Pages = {57--71}, Publisher = {Elsevier Science Publishers Ltd.}, Title = {Past Pushdown Timed Automata and Safety Verification}, URL = {http://dx.doi.org/10.1016/j.tcs.2003.10.004}, Volume = {313}, Year = {2004}, acmid = {985571}, bdsk-url-1 = {http://dx.doi.org/10.1016/j.tcs.2003.10.004}, date-added = {2014-10-29 12:51:43 +0000}, date-modified = {2014-10-29 12:51:43 +0000}, issue_date = {16 February 2004}, numpages = {15}, doi = {10.1016/j.tcs.2003.10.004} }